It looks like the futuristic power system for electric cars promised by EEStor could be a little late.

EEStor CEO Richard Weir told CNET News.com in a brief phone interview that commercial production of its energy storage system--a device that holds electricity and functions somewhat like a battery--will be sometime in the next 10 months or so. The unit is also referred to as an "ultracapacitor."

"We intend to be in production on or before the middle of next year," he said.

Although that means that the company could be in production by tomorrow, the time frame is a little wider, and extends about six months or so further into the future than previously stated.

Back in January, the company stated that it would start shipping 15 kilowatt hour electrical energy storage units to Canada's Zenn Motors, its first customer, in 2007. Zenn's cars will mark the first commercial application of EEStor's technology.

EEStor has been somewhat secretive about its technology, but proponents claim it will revolutionize the automotive industry because it will deliver electrical storage units that can power cars for hundreds of miles and can be recharged in minutes. By contrast, lithium-ion batteries now being prepared for cars take hours to charge and can take cars 200 miles or less. Skeptics have wondered whether EEStor can live up to its claims.

A six-month delay isn't that serious of an issue for a start-up, and a number of clean-tech companies have faced delays this year. Tesla Motors had to postpone its electric cars a few months, while in solar both Miasole and DayStar Technologies have had delays. So has GreenFuel Technologies, which wants to turn algae into fuel and clean carbon dioxide from the environment. But it's not great news either, and underscores the difficulty of bringing some of these green technologies to market.

Zenn, which invested in EEStor earlier this year, currently sells low-speed electric cars that run on more conventional batteries. These low-speed cars, which are similar to those made by other small manufacturers like Miles Automotive, are designed for campuses and retirement communities. The U.S. Department of Defense has also launched a program to buy a significant number of low-speed vehicles.

For more information, you need to go to Zenn's Web site. EEStor doesn't have one.

You can't learn a lot from looking at the Web site of Kleiner Perkins Caufield & Byers either. The firm is reportedly an investor in EEStor, but EEstor is not listed as a portfolio company on the firm's site. Venture firms, however, do this at times with stealth companies.